Well seems nobody wants to take on the question, The short answer is "it depends."
It's actually a really good question. Nobody really knows the answer. They base how they do it on observation.
Some, water beforehand then water with fertilizer. I feel if doing 1/4 or 1/2 doses ones does not need to do this. With diluted doses I water like you would if no fertilizer. Saturate till it runs out. Better to water heavy at longer intervals than to water a little at shorter intervals. this is the accepted practice, and why would you change it when adding fertilizer? I'm sure others have their on way of doing things. You yourself have to decide what works for you.
Many here advocate a one size fits all approach. Same fertilizer, same dose for all plants. Through decades of observation I have found this to be invalid. Some say the ratio is the same for all plants. Again, this is not true. Uptake of nutrition varies by plant family, sometimes even within a plant family. Nutritional adaptations for each plant group do vary. Some use bacteria to help, vascular plants use fungi, well 90% do. Some do not like Cabbage.
Some convert animal protein to nitrogen, Using chemical fertilizers can easily kill them. Some can move nutrients both ways root to shoot, or shoot to root. When you asked about foliar feeding, well it depends if the plant you are feeding has the ability to move nutrients from leaves to roots.If it only feeds the leaves, other parts of the plant could be at a deficit.
In a nutshell, how you feed a plant, what doses to give, what ratios work best depends on what you're feeding.

Because of this I myself have decided to just feed the soil, and the plant can take what it needs.. Most soluble fertilizers damage the soil, so I don't use them. It really is near impossible to know if you're giving enough or not. I would suggest to follow label instructions. and modify. Say it calls for 1 tablespoon per gallon once every two weeks. And you water your plant once a week. So give 1/2 dose at each watering.Still I don't trust the labels that much. So I'm moving away quickly from chemical fertilizers. I prefer a liquid organic like say Sea Mate. It was easy to switch to organics using liquids for house plants. It also requires a change in soil makeup. Each grower has to decide what works for them. With cacti, which I grow. I have been hesitant to do this as pretty much exact doses and ratios for cacti have been figured out via various studies. Following study findings I have had great success, so I may stick with soluble for them. I don't use foliage pro as the ratio is incorrect for my methods. I have said this before and others came forward calming great results with foliage pro. Sure they will grow fine with this, but they will grow even better using study supported techniques. I have no desire to tell people what to do, we are all adults here, do what works for you, and I'll do the same. I like my method of using 2 different fertilizers as I'm also trying to keep soil somewhat acidic, It works for me, use what works for you.
Hopefully I answered your questions. Good luck!

Since the previous answer is a bit convoluted and doesn't really answer your question, let me try :-)

How much you need to water - with fertilizer or not - depends on the size of the container. An entire liter of water for a small 4" or 6" pot is too much but may be just right for a larger plant in a 12" pot. I am of the watering before fertilizing camp so I water the plant sufficiently to the point where water runs through and out the drainage holes. Once that stops, I water again with the dilute fertilizer until it does the same. Done!

The dilution allows you to fertilize more frequently, which is often beneficial with containerized plants since frequent waterings tend to leach or wash out any lingering nutrients and these need to be replaced.

Some folks like to make fertilizing into this big scientific study but it is really not that necessary to go into great depths. Studies have shown that most plants will respond to the basic plant nutrients the same way and have similar nutrient demands that must be addressed in a container setting. I fertilize ALL my containerized plants - both indoors and out - with the same products: a CRF at planting and supplemental water soluble fert during the primary growing season. All of them thrive under this sort of simplified program.

FWIW, there is no evidence that soluble fertilizers 'damage' soil......not sure where that comes from so feel free to use as desired. Also, unless a carnivorous plant, no plant can directly break down animal protein to nitrogen. That requires the activity of soil biology and since soil biology is scarce to nonexistant in a high quality potting soil, one applies nitrogen in an immediately plant accessible form via a soluble source. And it is important to remember that plants do not care how the specific fertilizer is sourced - organic or synthetic, by the time it is able to be taken up by the plant roots, it is in the exact same soluble salts form.

And finally, fertilizer is most efficient when applied to the soil. Very little nutrient absorption is available though the foliage - the majority of nutrients that plants requires are accessed by the root system.

Super simple answer: Follow what's on the label. Seriously, they know what they're doing.

More in depth:

Container fruit trees and ornamentals in growing season:
Foliage Pro 1/2 strength every watering
OR: full strength Osmocote or Dynamite with no liquid ferts
OR: 1/4 strength foliage pro and 1/2 strength Osmocote
OR: full strength Vigoro per directions on bag

-Veggies:
Full strength Foliage Pro
OR: Go organic with dry and liquid ferts in ratios listed on packaging. I like General Organics Biothrive and Dr. Earth or Jobes.

Did you have chance to read this thread? You'll probably find answer to your question and/or ask:

about fertilizing-click here

Hi all,

Thanks for all the tips. Definitely helps. I am new to all this, so just trying to learn from everyones experience.

Cheers

Ben

Hi,

One more question. I have two citrus in a gritty mix with CRF and some gypsum.

I have also ordered some foliage pro (if it gets through customs). Is ti too much to fertilise with foliage pro with a CRF already in there?

Cheers,

Ben

Yes Ben you can, and most of us DO use a water soluble fertilizer with CFR already in the mix. Calistoga Al

There are a number of variables that dictate the most efficient way to fertilize. For instance, you wouldn't fertilize as often or at the same strength when using a water-retentive soil that forces the grower to water in sips as you would in more open soils that allow the grower to flush the soil of accumulating salts every time the planting is watered. IOW, your soil choice and watering habits are inextricably linked, and ultimately determine the best way to fertilize.

Using soils that force the grower to water in sips have inherent issues related to fertility. When you water in volumes smaller than required to flush the soil, accumulation of soluble salts in the soil solution from fertilizers and what's dissolved in tap water are a given and a double barrel problem, the first being an ever-rising EC/TDS (salt level in the soil solution), and a nutrient ratio in the soil solution that can quickly become badly skewed. Because of what causes them, badly skewed ratios are usually accompanied by high salt levels in the soil solution and antagonistic deficiencies, which occur when a level of one or more elements is too high, making it difficult for plants to take up one or more other elements. A prime example often occurs when using bloom booster fertilizers. The excessively high levels of P cause several unwanted issues, one of which is difficulty taking up a number of nutrients, but especially Fe (iron).

The easiest way to take precise control over how much of what your plant gets (in terms of nutrients) and when it gets it is by using a soluble synthetic fertilizer that supplies nutrients in a ratio that closely mimics the ratio at which the plant actually USES nutrients.

One day, I decided to define what nutritional supplementation goal would best suit plants grown in containers. Here is what I came up with:

Nutrient Supplementation - Objectivity
Whenever we discuss what is or isn't an appropriate part of the methodology we use to make certain our containerized plants get all the nutrients essential to growth and good health, we would probably first want to be sure our objectives are on target. It's difficult to argue with the idea that our focus in supplying supplemental nutrition to our plants should be on ensuring all the nutrients plants normally assimilate from the soil are A) IN the soil and available for uptake at all times, B) in the soil in a favorable ratio - that is to say in a ratio that mimics the ratio at which the plant actually uses the nutrient, C) at a concentration high enough to ensure no nutritional deficiencies, yet still low enough to ensure the plant's ability to take up water, and the nutrients dissolved in that water won't be impeded (by a high concentration of solubles in the soil solution).

At this point, you can accept these premises as worthy goals or argue against them. If accepted, we should then necessarily examine our efforts at supplementation in the light of whether or not our efforts bring us closer to or limit our ability to see the goals implemented.

Al

Not a stupid question at all. I had the same problem. In the end I'm doing the same as Drew. I just water the soil and the plant does the rest. Develop a feeling for when the soil is saturated and the plant will be happily fed......:-)
(wanna know a big secret..... Get a good quality Humic acid. It will blow you away)

This post was edited by fredman on Thu, Dec 11, 14 at 15:04